Pressure relief valves are sometimes used to regulate or control pressure of a structure. Generally speaking, a pressure relief valve can include a poppet or other structure connected to a spring. The poppet can be placed into a valve, cylinder, or other structure that can be used to provide a valve body for the pressure relief valve. The spring can be configured such that the spring has a tension that approximately matches a pressure at which the pressure relief valve is to open. For example, a spring can be configured to apply a force of about five pounds per square inch to the poppet. As the tank pressure approaches or exceeds five pounds per square inch, the pressure in the tank can overcome the pressure relief valve spring and can cause the pressure relief valve to open, thereby relieving pressure within the tank. A pressure relief valve also can be used to regulate negative pressures by inverting the structure of the pressure relief valve so that an ambient pressure works against the spring instead of an internal pressure.
In some applications, a narrow range of operating pressures can result in a requirement for very exact spring selection or tensioning and/or other mechanisms to ensure proper operation of the pressure relief valves. Because mechanical devices such as springs, poppets, and the like may not be exact, may wear over time, and/or otherwise may not provide exact tensions or otherwise perform optimally, pressure relief valves may open at pressures above or below the target pressures and/or may progressively open until the valve is completely open at the target pressure. If exact pressures are needed, for example for pressurized fuel systems or other closed vessel applications, such pressure relief valves can adversely affect performance or cause other problems.
Similarly, in operation, a pressure within the tank or other regulated or controlled structure may not be constant or predictable. For example, the pressure within a fuel tank, for example, may not increase gradually and/or in a smooth manner. Rather, the pressure in the tank may approach the target pressure and may have periodic excursions into or near pressure values that can cause the valve to open partially and/or completely. Routine excursions into the range at which the valve begins to relieve may cause some fluttering or leaking of the valve.
It is with respect to these and other considerations that the disclosure made herein is presented.